1. Field of the Invention
The invention concerns liquid and bar soap compositions with enhanced fragrance properties.
2. The Related Art
Soap is a chemical term for salts of C10-C24 fatty acids. Personal care compositions such as, but not limited to, liquid cleansers, toilet bars, shampoos, shaving compositions and deodorant/antiperspirant formulas may incorporate substantial amounts of soap. The fatty acid raw material invariably includes some small amount of lower molecular weight acids. These may be C4-C8 acids. These present a malodor issue.
Short chain acids are volatile. It takes very little of these materials to have a large negative sensorial impact. For instance, hexanoic acid (caproic acid) has the odor of limburger cheese. Butyric acid is described as simply having an obnoxious odor. For these reasons, soap containing formulations require odor masking compounds and/or a cover of pleasant fragrance emitting substances.
Representative disclosures of soap formulations are herein described. U.S. Pat. No. 5,147,574 (MacGilp et al.) disclose liquid dispersoidal cleansing compositions including 5-20% saturated higher fatty acid potassium soap, 3-18% of free fatty acids, wherein the soap and free fatty acids have a ratio of about 1:0.5 to 1:1.
U.S. Pat. No. 5,308,526 (Dias et al.) reports a stable mild dispersoidal liquid soap having 5-20% potassium C8-C22 fatty acid soap, 0.1-7% of C8-C22 free fatty acid, 35-70% water and a polyol, petrolatum and glycol ester.
U.S. Pat. No. 5,312,559 (Kasher et al.) reports a mild soap personal cleansing and moisturizing composition including C3-C22 free fatty acid soap, C8-C22 free fatty acid, water and emollients.
U.S. Pat. No. 5,851,978 (Shana'a) reports an aqueous cleansing and moisturizing composition that includes 5-35 weight % of C8-C22 fatty acid and up to 10 weight % of a surface active agent.
U.S. Pat. No. 6,906,016 B1 (Tsaur) details liquid cleansers which comprise a water soluble or water swellable starch combined with linear C8-C13 fatty acids.
U.S. Patent Application Publication 2005/0020461 A1 (Seki) describes a cleansing composition with 20-50% of fatty acids and salts thereof, wherein the content of fatty acids having 20-24 carbon atoms is from 10-30% by weight of the total fatty acid components, and a weight ratio of fatty acids having not more than 15 carbon atoms to fatty acids having not less than 16 carbon atoms is in a range from 20:80 to 50:50.
Finally, U.S. Patent Application Publication 2005/0220736 A1 (Polonka et al.) reports partially neutralized fatty acids in compositions that deliver enhanced visual benefits to the skin with specific optical attributes. Most of the aforementioned patent documents disclose use of a perfume (fragrance) in the compositions.
Fragrances can be quite expensive, and since they are a mixture of many components, it is difficult to know which have the best suppressant effect against short chain fatty acid malodor. It would be useful to combine the most appropriate soap base with the most efficient fragrance component(s) to achieve the most cost effective and best aesthetic result.